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vco1-first.md

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First test of Demo VCO1

Examine on scope

Since Demo VCO1 will always generate at least one channel of output, we can look at that output with the VCV Fundamental Scope without needing to make a patch which outputs audio.

Let's look at the different waveforms using Scope:

Each of the three different waveforms output by Demo VCO1 being displayed in three VCV Fundamental Scope modules

We can see some good things here. The basic shapes of all the waveforms look correct, with no obvious gaps, jumps, or other strangeness. The output voltage swings between +5V and -5V as desired (except the crazy parabolic - more on that later).

Now let's check out the tuning. First - with no input (zero volts) the VCV spec says we should put out a frequency which is equivalent to a musical note at a pitch of C4, also known as Middle C.

Here we are using NYSTHI Hot Tuna to check the pitch:

Initial tuning check of Demo VCO1's sine wave using NYSTHI Hot Tuna

Now, let's see if Demo VCO1's sine wave tracks at 1V/Octave like it's supposed to. Here we again use Hot Tuna to check the pitch, VCV MIDI-CV to generate precise voltages, and NYSTHI MultiVoltimetro to display the voltage.

Negative 2 volts showing a pitch of note C2

Negative 1 volt showing a pitch of note C3

We see that the pitch changes by an octave when the CV changes by a volt.

So far, it looks like Demo VCO1 is working perfectly, but in our next session we will dig a little deeper and find some pretty bad flaws in how it works.

The next page discusses CPU consumption.